Castiel's battle with Lucifer leaves him completely insane, while a studious young cellist becomes a reluctant prophet.
Last week's Supernatural left a mysterious, earthy lump with Sam and Dean Winchester; this week they take a hammer to it. This has two major effects: Castiel comes out of his coma, and some poor Michigan kid named Kevin gets zapped by lightening. Kevin is knocked out and misses a crucial math test, but it's all good because, as he says, he's the chosen one by birthright and has to keep going -- in other words, a little nutso.
Speaking of nutso, Castiel's first move upon waking is to make fart jokes and theorize about flower organization. Fortunately, he is able to shed some light on Sam and Dean's mystery stone: it's none other than the verbatim Word of God, though which word it may be he's a little less clear on.
The Angry Angels
While Dean does his best to get through to the fractured Castiel, Sam recruits Kevin to try and decipher the mysterious Word. He deciphers enough to reveal that it's a history of the Leviathans, but the process is pretty draining. Before he can finish the decryption, the group is beset by a pair of angels calling him a prophet and attempting to take him away. They escape and hit the road.
Unfortunately, all this magical activity makes the crew pretty easy to trace: Meg kills two of Crowley's demons, leading the angels straight to their hideout. Hester nearly kills Castiel, but Meg intervenes to stab her.
Blood of the Fallen
Kevin manages to complete his translation of the Word--Leviathans can be slain by a righteous mortal bathed in the blood of three fallen, obviously--and the remaining angels agree to watch over him at home. Unfortunately, there's already a Leviathan on site: he makes short work of both angels, and now holds all the cards.
At this point in the season, it makes sense to judge Supernatural episodes such as these based on how well they set up a bad-ass final confrontation: by that measure, I'd call tonight's episode a success. It's nice to see the show's Biblical elements tying in with the Leviathan plot, and even if the super specific Leviathan killing process is a little Deus ex Machina, that's pretty much how mythological stories have always worked. Hopefully this blood of the fallen angle will lead to a good Season 7 payoff.
"I'm not a nurse, just playing one on TV."
-- Meg, fourth wall-break!
"Pull my finger."
-- Castiel, before blowing the lights out
"You guys ate the apple, invented pants..."
-- Castiel, on evolution
"No. You're playing Sorry."
-- Castiel and Dean, going a bit literal there
"This looks like a sex torture dungeon. Is this a sex torture dungeon?"
-- Kevin, on what is not actually a sex torture dungeon